This tip has apparently been around for quite a while, but the indispensable macosxhints just discovered it today, and I thought I'd share the love. It turns out that, using iMovie and at least one picture/video file, you can chose a couple of specific export options to crank out a DRM-free AIFF file from any of your iTMS songs. Bringing this file back into iTunes, of course, re-converts and compresses it to your bidding. It might be a roundabout solution, but if you can export more than one song per iMovie project (anyone care to try?), I bet this could turn out to be a bit easier than burning all those CDs.
Check out macosxhints for the full instructions on using iMovie to de-DRM your tracks.